Smoke screen generator



June 11,1946. G- 1 HOL-[HAM l SMOKE SCREEN GENERATOR Filed May 21, 1943` Patented June 11, 1946 UNITED STATES PATENT OFFICE SMOKEr SCREEN GENERATOR y Gerald .L Holtham, United States Navy Application May 21, 1943, Serial No. 487,872

(Granted under the act ofV March 3, 1883, as

6 Claims.

yhot exhaust-pipes asa part of their regular equipment.v

n ninrtherfobject of this invention is'to provide a l'smoke screen-"generator for laying'down a u smoke'screenabout the boat or vehicle to which amended April 30, 1928; 370 0. G. 757) straps encompassing both the chamber 2I and the pipe I2.

Extending upwardly from the chamber memg ber 2| are' two threaded nipples 22 and 23. The

it is applied; thereby enabling the vehicle to quickly generate asmoke screen for hiding itselfl as Well vas for concealing other vehicles Aor objects from Y enemyi observation.

'y A further object of this invention is to provide an eliicient smoke generator which may utilize either fuel oil or fuel oill and water for providing a smoke or smoke andsteam cloud for concealment purposes. V

With the foregoingY and other objects in View, the-invention consistsin the construction, combination and arrangement of parts hereinafter described and illustrated inthe drawing in'which:

Fig. is a perspective view of the smoke screen generator of this invention;

and 3j and Y Eig.' 3 is a longitudnallandpartly sectional view showing the inner details'of-'the smoke screen generatorj There is shown atr I0 the smoke screen generatorof this invention. This smoke screengenerator I0 includes the conventional exhaust pipe II attachedin the usual manner to the engine (not shown) of the vvehicle or boat on which this invention is'being used.

No muiiler to be used with this installation. Instead of v"discharging `to the atmosphere, this exhaustfpipe II is led into a somewhat larger pipe' I2'4which`willbe Supported around the end I3 'by suitable `flanges I4 and I5, whichV serve Vto spacewthe end section Iiiirom the inner surface of the end I6 of the exhaust pipe II, thus providing an annular chamber II between the concentric ends of the exhaust pipes I I and I2. This end I6 of the outer pipe I2 is provided with a plurality of small perforations I 8 and with a threaded nipple 2|).Y o

Adapted to be placed over and to completely enclose the apertures I8 is a chamber member 2| which may be made of a small semi-cylindrical ysection of pipe having its ends closed so that when it is mounted on the upper side of the pipe I2 over the apertures I8, it will make a gas tight nt therewith. It may be permanently Yat ,into vapor or smoke.

nipple 22 has threaded `therein a clean-out plug 24 allowing access to the interior chamber I9 of chamber member2l. Threaded nipple 23 has an oil supply pipe 25 threaded therein, a control valve 26 being secured inthe pipe 25 adjacent the chamber 2|. The nipple 23 extending to the end of pipe I2 directly to the chamber II is provided with a water pipe 21 and a control valve 28 therein.

In operation, the outer concentric pipe I2 is mounted over the end I3 of the Vehicle exhaust pipe II and supported thereabout by means of the flanges I 4- and I5 so as to provide the annular chamber lI therebetween. When it is `desired to generate va smoke screen the valves 26 and 28 are operated as l'desired so to feed fuel oil thereto. The oil from the pipe 25 is fed into the chamber I9 and lands on the hot outer end of the pipe I27 thus receiving preliminary heating, then enters through Ithe perforations I8 into the chamber I-l and contacts against the hot end I3 of the `exhaust pipe SII, thus being changed When the valve 28 of the water pipe 2l is manipulated, water entering from pipe l2`I into lthe same chamber -I'I is turned into steam by contacting the hot end I3, .of `the exhaust pipe vI I. -By proper manipulation the proportions of steam to smoke may be controlled if desired or the steam may be entirely omitted by "keeping valve 28 closed as may be desired.

The `combustion gases which pass through the pipe II continue through ythe end I3 through the pipe I2 to'wherever it maybe directed ,at an edge of the ,Vehicle or boat'im which it is mounted. As 'the combustion gasesleave the end I3 of exhaust pipe I I, they produce a Venturi eiect, thus creating a vacuum about the ends of chamber I'I and tending to draw in the smoke or mixture of smoke and steam produced in the chamber I'I, thus mixing the smoke with the combustion gases which then discharge at the outer end of the pipe I2 to provide the smoke screen desired.

InV the case of small boats, gasoline engines are generally used so that exhaust pipe I I would have combustion gases therefrom, but the invention is equally applicable when the engines of the vehicle are Diesel engines using fuel oil as the source by those skilled in the art without departing from the nature of what is hereinafter claimed.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any -royalties thereon or therefor. f

What is claimed'is:

1. A smoke screen generator comprising an exhaust pipe, a concentric pipesecured about said exhaust pipe adjacent lits end to provide an annular chamber therebetween, and means for ieed.A ing smoke generating material through said concentric pipe onto said exhaust pipe to vaporize the smoke generating material.

2. A smoke screen generator comprising an exhaust pipe, a concentric pipe securedabout said exhaust pipe adjacent its end to provide an annular chamber therebetween, and means for feeding smoke generating material through said concentric pipe onto said exhaust pipe to vaporize the smoke generating material, the edge of said exhaust pipe being so spaced from the, inner surface of said concentric pipe as to provide a Venturiefect and create a vacuum drawing the vaporized smoke generating material into the combustion gases passing therethrough.

3. A smoke screen generator comprising an exhaust pipe, a concentric pipe secured about said exhaust pipe adjacent its end to provide an annular chamber therebetween, and means for feeding smoke generating material through said conthe invention, within the scope of centric pipe onto said exhaust pipe to vaporize the smoke generating material, the edge of said exhaust pipe being so spaced from the inner surface of said concentric pipe as to provide a Venturi eiect and create a vacuum drawing the vaporized smoke generating material into the combustion gases passing therethrough, said feeding means including a chamber member secured to the outer surface of said concentric pipe over said inner extending exhaust pipe, said concentric pipebeing provided with perforations leading from the chamber of said chamber member through said concentric pipe to said annular chamber between the concentric pipe and said excentric pipe onto said exhaust pipe to vaporizel the smoke generating material, the edge of said exhaust pipe being so spaced from the inner surface of said concentric pipe as to provide a Venturi effect and create a vacuum drawing the vapcrized smoke generating material into the com.- bustion gases passing therethrough, said -feeding means including a chamber member secured to the outer surface of said concentric pipe over said inner extending exhaust pipe, said concentric pipe being provided with perforations leading from the chamber of said chamber member through said concentric pipe to said annular chamber between said concentric pipe and said exhaust pipe.

4. A smoke screen generator comprising an ex- 45 ecentric haust pipe, a concentric pipe secured about said exhaust pipe adjacent its end to provide an annular chamber therebetween, and means for feeding smoke generating material through said conhaust pipe, and a valved conduit discharging into said chamber member.

5. A smoke screen generator comprising an exhaust pipe, a concentric pipe secured about said exhaust pipe adjacent the end to provide an annular chamber therebetween, and means for feeding smoke generating material through said concentric pipe onto said exhaust pipe to vaporize the smoke generating material, the edge of said exhaust pipe beingv so` spaced from the inner surface of said concentric pipe as to provide a Venturi eiect and create a vacuum drawing the vaporized smoke generating material into the combustionV gases passing therethrough, a chamber member Asecured to the outer surface of said concentric pipe over said innerv extending exhaust pipe, said concentric pipe being provided with perforations leading from the chamber of said chamber member through said concentric pipe to said annular chamber between said concentric pipe and said exhaust pipe, a valved conduit discharging into said chamber member, and a water pipe leading directly through the said concentric pipe to said annular chamber between said contric pipe and said exhaust pipe end.

6. `Asmoke screen generator comprising an exhaustpipe, a concentric pipe sec-ured about said exhaust pipe adjacent its end to provide an annular chamber therebetween, and means for feeding smoke generating material throughsaid conpipe onto said exhaust pipe tol 'vaporize the smoke generating material, the edgefof said exhaust pipebeing so spaced from the inner surface of said concentric pipe as to provide a Venturi effect and create'a vacuum drawing the va- 0 porized smoke generating material into the comfbustion gases passing therethrough, a chamber member secured to the outer surface of said concentric pipe over said inner extending exhaust pipe end, said concentric pipe being provided with perforations leading from the chamber of said chamber member through said concentric pipe to said annular chamber between said concentric pipe and said exhaust pipe, a valved conduit discharging into said chamber member, and a clean- O out plug secured through said chamber member.

' GERALD J. HOLTHAM. 

